Final answer:
A graylag goose is most likely to retrieve an egg if found outside her nest due to innate behavior that increases its fitness and chances of survival.
Step-by-step explanation:
A goose, such as a graylag goose, is most likely to retrieve an egg that has rolled out of her nest. This behavior is described as innate, which means it is hardwired into the animal's instincts, and egg rolling back into the nest helps ensure the survival of the species by keeping the eggs safe until they hatch. This action directly increases a goose's fitness by improving the likelihood that her offspring will survive to maturity and themselves reproduce, thus passing on the mother goose's genes.
The mother goose's action of returning the egg illustrates how innate behavior is crucial for the survival of species in the wild. In birds, particularly those that nest on the ground, such as ducks and chickens, these behaviors are essential as their hatchlings are vulnerable to predators. Hence, protecting the eggs before they hatch is vital for the continuation of their line.